User blog:Bobnekaro/Watch out for the Atlantic in August - U.S. impacts possible
So, the Atlantic is completely dead right now. No tropical cyclones have existed in the basin since June 21, when Tropical Storm Danielle dissipated over central Mexico. The 2016 season had a record start, with 4 named storms forming before July. However, we still await our fifth storm, which would be named "Earl." None of the three major models - ECMWF, GFS, and CMC - currently forecast Earl to develop in the next two weeks. However, Atlantic conditions are expected to improve dramatically in just a couple weeks. The current Atlantic inactivity is caused by three main factors: the Pacific hyperactivity, the sinking MJO phase, and the Saharan Air Layer. All of these three factors are expected to ease in August. Pacific Hyperactivity Right now, the Pacific is in a very hyperactive phase. Since July 1, the Pacific as a whole has seen 5 named storms, 4 hurricanes/typhoons and 2 major hurricanes/typhoons. The East Pacific has seen Agatha, Blas, Celia, and Darby, while the Western Pacific witnessed the powerful Super Typhoon Nepartak. The hyperactive Pacific phase is being caused by an upward phase of the Madden-Julian Oscillation (MJO) which is providing favorable conditions for tropical cyclones to develop. Generally, an active Pacific is correlated with an inactive Atlantic at the same time, and this is no exception. While June featured the existence of three storms in the Atlantic - none existed in the Pacific. July has been a Pacific-predominant month - but August is likely to be different. In years with an El Nino-La Nina transition, Pacific hyperactivity early in the season is not uncommon. For instance, the 2010 Pacific season featured 4 named storms and 2 major hurricanes before July, including a category 5 hurricane - but after July 1, the season was nearly dead, with 4 named storms and only one category 1 hurricane. No hurricanes formed after late August. I expect the Pacific to cool off tremendously in August when a sinking MJO phase likely arrives, coupled with a trade wind burst that is likely to cause cold water upwelling in the Pacific - this should allow for a weak La Nina to develop by the fall. Based off the current activity trends...I would not be surprised if July ends up being the Pacific's most active month of the year. Sinking Air Since mid-June, the Atlantic has been in a sinking phase of the MJO. Sinking air is hostile to tropical cyclone formation. This sinking air is expected to leave the basin later this month. Once rising air arrives, Atlantic conditions are likely to become more favorable. Saharan Air Layer This month, the Atlantic has seen many Saharan Air Layer (SAL) outbreaks in the basin. This dusty, hot, dry air is hostile for Atlantic tropical cyclogenesis. It usually causes tropical waves moving off the African coast to remain weak and not develop further. What August May Be Like All of the three factors are expected to ease in August. If the upward MJO phase arrives, Atlantic conditions should become quite favorable for Atlantic development in August. The Saharan Air Layer is likely to have less outbreaks as we approach the peak of the season. -NAO conditions should allow for some more warming of the Atlantic Main Development Region (MDR) which already has above-normal SSTs. The current placement of the Azores High is likely to cause Cape Verde-type storms to track farther west rather than on a typical northward out-to-sea track. Hurricanes this season are more likely to track towards land, as troughing has not developed over the east coast (troughs usually direct storms out to sea and away from land). The United States may need to be on high alert in August if tropical waves and cyclones reach the western Atlantic. Waters in the northeastern Gulf Of Mexico have warmed to a sizzling 31-32C, which is warm enough to support rapid intensification. SSTs are also very warm in the Western Atlantic and Caribbean, the latter of which waters are warm to great depth. All of these factors may allow for a strong, possibly landfalling hurricane to develop in the Atlantic sometime during the month of August. Category:Blog posts